With the development of wireless communications, an Active Antenna System (AAS, Active Antenna System) is applied to communication systems increasingly. The AAS is mainly characterized in that an antenna element is directly connected to a transceiver so that each element is used by only one transceiver. A Radio Frequency (RF) front end of n paths of AASs includes Ant element (an antenna element, also called an antenna oscillator) which is connected to a duplexer (DUP, DUPlexer). The DUP is connected to a receiving channel and a power amplifier separately. Generally, an antenna includes multiple paths of antenna elements so as to achieve a transmitting or receiving gain of a signal.
In the process of researching the present invention, the inventors find that great power loss is caused when an AAS and a passive antenna multiplex an antenna element by adopting a conventional combining technology (namely, in a direct combining manner).